MR GUIDEWIRES

An MR safe medical device

  • must be non-ferromagnetic so that it does not dislocate in the magnetic field
  • must not be electrically conductive
  • must not heat up during MRI
  • should not create imaging artifacts that obscure or distort the image of the target.

 

MaRVis´ integrated platform technology for the first time enables the necessary combination of high axial stiffness, torsion capability, general stability, flexibility and tear-resistance as essential material properties of an MR safe guidewire and patient safety features, controlled artifact generation for directed visualization, and no electric conductivity or heating in MRI.

See also: www.researchgate.net/project/MR-Marker-System-for-Interventional-MRI-Devices



Fig. 1-1

The basic material for the design of MaRVis Guidewires is an ultra-thin rod-shaped novel composite material („MaRVis rod“, Fig. 1-1) consisting of glass and/or aramid fibers and epoxy resin. Metal particles as MRI visualization markers can be embedded in the epoxy resin.

0.035“ standard (Fig. 1-2) and stiff (Fig. 1-3) MaRVis Guidewires are composed of several MaRVis rods embedded in an envelope polymer and covered by a PTFE shrink tube as the outer surface. The micro MaRVis Guidewire (0.014“) is composed of one MaRVis rod and a PTFE shrink tube. The MaRVis rods essentially contribute to the controlled good mechanical properties of the MR guidewires.

As these guidewires are electrically non-conductive and do not heat during MRI they are MR safe (they do no comprise a continuous metal core!).

Fig. 1-2
Fig. 1-3


The multi-composite design of the devices provides a huge flexibility in product design and high mechanical product safety, especially by the extreme tear-resistance of aramid fibers and the very high elasticity of PTFE shrink tubes. A MaRVis Guidewire provides high stiffness (adapted to the respective type of guidewire) and transmits compressive and tractive forces as well as torsional moment. This design allows handling according to today's established standards.

The choice of the specific MR marker particles, their concentration and the centralized localization of the particles lead to a very sharp and precise representation of the MaRVis Guidewires in MRI.

 

Table 1-1 summarizes the essential design requirements and the solutions realized in the MaRVis Guidewires.

RequirementSolution
Flexibility in product design
  • multi-composite design
  • unique standard, stiff and micro guidewires
  • unique stylet (mandrel) prototype
Flexible tip
  • ground and coated (single piece, no attached parts!)
  • plastically shapeable tip
Patient safety tear-resistance upon kinking => no disruption of guidewire and no surface impairment
Mechanical handling

equivalent to commercial guidewires

=> allowing short procedure times
Good MRI visibility in all orientations
„as used to“

specific MaRVis MR markers: metal particles

  • continuous image (line as in X-ray)
  • extra ball-shaped tip marker for tip identification
  • well balanced artifacts longitudinal and perpendicular to B0


Routine application of MRI-guidance for endovascular interventional procedures now will become possible. In addition, novel medical therapies will be enabled which strongly benefit from the advent of MRI-guided interventions and MR safe guidewires.

The MaRVis platform technology for MR safe medical devices, the MaRVis Guidewires and other medical devices which can be derived from the proprietary basic materials, and the manufacturing technologies are protected by a broad and comprehensive patent portfolio and comprehensive know how.

MaRVis Interventional GmbH

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